Presumptive Democratic presidential nominee Joseph R. Biden said Monday President Trump has done more to shield the White House from the coronavirus than he has to protect the general public.

The former vice president said Mr. Trump could push the nation toward “reopening the economy” by following through on the unfulfilled promise that “anybody that wants a test can get a test.’”

“The administration is fully aware that this is the right path, too — after all, the president and his staff are now reportedly receiving daily tests,” Mr. Bidenwrote in a Washington Post op-ed. “They knew exactly how to make the Oval Office safe and operational, and they put in the work to do it.”

“They just haven’t put in that same work for the rest of us,” Mr. Biden said. “If Trump and his team understand how critical testing is to their safety — and they seem to, given their own behavior — why are they insisting that it’s unnecessary for the American people?”

The coronavirus crisis has pushed Mr. Biden off the campaign trail and become a central part of his message as he looks to weaken Mr. Trump ahead of the fall election.

“His goal is as obvious as it is craven: He hopes to split the country into dueling camps, casting Democrats as doomsayers hoping to keep America grounded and Republicans as freedom fighters trying to liberate the economy,” Mr. Biden said. “It’s a childish tactic — and a false choice that none of us should fall for.”

Polls show more than half of voters disapprove of the Trump administration’s response to COVID-19, the disease caused by the new coronavirus, and that Mr. Biden has a 4-point edge over Mr. Trump in a head-to-head matchup.

Mr. Biden said Americans want the nation to “reopen as soon as possible” and said governors would be able to lead the way if they had more support from the president and the federal government.

“It’s been more than two months since Trump claimed that ‘anybody that wants a test can get a test,’ ” Mr. Biden said. “It was a baldfaced lie when he said it, and it still isn’t remotely true.”

Mr. Biden said the economy will not come back until people are confident they are safe and the number of cases start to level out or drop.

“Instead of once again seeking to divide us, Trump should be working to get Americans the same necessary protections he has gotten for himself,” he said.